Staff members and workers at the US Capitol, line up as they return to the building following an evacuation

U.S. fighter jets scrambled to intercept a small plane that entered restricted airspace over Washington Wednesday, forcing the evacuation of the White House, the U.S. Capitol and other federal buildings. The two aboard the aircraft, a student pilot and his instructor, were taken into police custody.

A small Cessna aircraft entered the security zone over Washington, prompting alerts across the city. Fighter jets escorted the plane to Frederick, Maryland.

President Bush was away from the White House, riding his bicycle in nearby Maryland.

Vice President Dick Cheney was at the White House, and was briefly evacuated. Mrs. Bush and former first lady Nancy Reagan, who was visiting with her at the White House, were taken to a secure location.

White House spokesman Scott McClellan says the plane ignored calls from air traffic controllers and entered the restricted zone around Washington, coming within five kilometers of the White House and causing alert levels to reach their peak, code red, which signals an imminent terrorist attack.

"Let me just point out that the Cessna was traveling in restricted airspace toward the White House and Capitol. The pilot was not responding to efforts to communicate with the plane," Mr. McClellan says.

The alert levels were reduced minutes later once the aircraft turned away.

At the Capitol, U.S. lawmakers, staffers, reporters and visitors fled the building, with police officers urging people to run.

Once authorities issued an all-clear signal and the Capitol was open for business again, Senate Majority Leader Bill Frist thanked security personnel for their efforts in keeping everybody safe.

"This is a huge Capitol building with literally hundreds and hundreds, indeed thousands of people, working in this complex, and having to stop and evacuate in an orderly way is a real challenge," Mr. Frist says.

Other federal buildings were also evacuated, including the Supreme Court and the Treasury building.